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Internal bridging issue?

Posted: Sat Jun 09, 2018 1:03 am
by kenour
I can't for the life of me figure out how to do this... Just designed a replacement dead blow mallet for my daughter with a hollow for a piece of round metal to be inserted into mid print.

Issue is I can't get it to bridge internally? What am I doing wrong?

All ready to go with supports.
1.PNG
This is when I would insert the steel rod.
2.PNG
Next layer should be a bridge, but it's giving it the external surface treatment, which obviously won't work.
3.PNG
How do I tell it that it needs to bridge there?

Cheers :)

Re: Internal bridging issue?

Posted: Mon Jun 11, 2018 6:52 am
by wirlybird
Go to the second to last tab on the right (I think) and on the left side are settings for bridging. The top setting for bridging area may be to high.
It may also be the geometry of the part that it see that area as a top layer instead of needing a bridge and more needing support.

Are you using concentric fill pattern also? that may be an issue.

Re: Internal bridging issue?

Posted: Mon Jun 11, 2018 1:53 pm
by TheBum
The problem is likely that you have a completely internal hole for the weight, so S3D is optimizing it out. If you cut the top of the mallet head off (as oriented on the bed in your picture) and print the mallet as two separate stacked objects, then that externalizes the hole and it should print with infill. You could leave off the top skin on the bottom piece and the bottom skin on the top piece. I think you might even be able to have the printer pause after the first process.

Re: Internal bridging issue?

Posted: Wed Jun 13, 2018 5:56 am
by kenour
Yeah I set it to 1 square mm, or whatever the lowest was. That's what I initially thought the problem was.

I only have 1 top and bottom layer set, concentric because it looks better on the mallet.

It seems to be treating the inside surfaces as top and bottom layers too, which if it acts like you're saying, it's giving it the concentric treatment (as shown in the photo, not the bridging treatment). I would have thought bridging would override it, but it seems like it doesn't.

I put the same model into Slic3r and it handles it perfectly. I triggered a filament change on my prusa just before it hit the bridge, dropped the weight in, and carried on. That was with the external layers set as concentric so it looked pretty :D

I'll keep fiddling!

Re: Internal bridging issue?

Posted: Wed Jun 13, 2018 9:57 am
by wirlybird
See what happens if you up the top layer count to 2-3 from 1. Maybe with it set at 1 it won't add a bridge since it still needs the top layer.

Re: Internal bridging issue?

Posted: Thu Jun 14, 2018 1:41 am
by kenour
wirlybird wrote: Wed Jun 13, 2018 9:57 am See what happens if you up the top layer count to 2-3 from 1. Maybe with it set at 1 it won't add a bridge since it still needs the top layer.
Just does 3 concentric layers. Weird, I'll try playing with the external fill pattern options.

Re: Internal bridging issue?

Posted: Thu Jun 14, 2018 5:27 am
by dkightley
This thread is getting painful!! The solution is simple...…

Use the Variable setting wizard with splits so that the internal upper surface has a separate setting to the rest of the model. Like this:
Capture1.JPG
Then, in the middle setting, change the External fill pattern to Rectilinear.


The model will now have bridging on the under surface of the included space, Like this:
Capture2.JPG

Re: Internal bridging issue?

Posted: Thu Jun 14, 2018 11:36 pm
by kenour
dkightley wrote: Thu Jun 14, 2018 5:27 am This thread is getting painful!! The solution is simple...…
Oh of course, that's so intuitive and simple compared to Slic3r... * slaps forehead* Silly me and everyone else. Well done you for knowing a thing, you're great :D :D :D